The Effect Of Cooking And Storage On Sensorial, Nutritional And Functional Properties Of Celeries

As the boom of catering and highly valued nutrition, it's very meaningful to study on how to keep the sensorial and nutritional quality of catering food during the cooking and distribution. Celery (Apium graveolens) is full of nutrition and bioactive compounds such as flavonoids. Celeries, cultivated all country around in four seasons, are one of the most popular green vegetable species used in catering. As a result, it's very important to study on the effect of cooking and storage on the quality changes of celeries. In this paper, the changes of sensorial and nutritional quality as well as bioactive composition on two kinds of celeries (Chinese celery and Western celery) during different cooking methods (blanching, steaming, microwave heating, stir-frying) and storage (cold storage, tempering storage) was studied. The main conclusions of this research are given as follows:(1)The effect of different cooking methods on sensorial and nutritional quality of celeries was studied. Results showed that the moisture contents and pH value were reduced while the total soluble solids contents increased after 4 kinds of cooking. Hardness and brittleness were reduced after cooking while the surface color was deepened. The chlorophyll contents on Chinese celery and Western celery after blanching were increased by 26.46%,18.34% respectively. Steaming, microwave heating, stir-frying reduced the chlorophyll contends of two kinds of celeries, but there were no significant differences. The contents of soluble protein and ascorbic acid on celeries after these 4 kinds of cooking methods were significantly lower than that on fresh celeries (P>0.05). Blanching made a decrease of 37.93% and 39.62% of soluble protein contents on Chinese celery and western celery. The ascorbic acid contents had a more than 50% loss after Stir-frying. The soluble protein and ascorbic acid on celeries were better reserved after steaming compared with other 3 kinds of cooking methods. Dietary fiber contents declined in both kinds of celeries after cooking.(2) The contents of total phenols and 5 kinds of flavonoids as well as antioxidant capacities in DPPH and FRAP system were also studied. The total phenol contents increased after cooking and the increasing degree was stir-frying>microwave heating >steaming>blanching. There was a similar increase on antioxidant capability. In FRAP assay, TEAC (Trolox equivalent antioxidant capacity) of Western celery changed after stir-frying from 3.69mg/100g FW to 12.48mg/100g FW. Total contents of 5 kinds of flavonoids detected on both Chinese celery and Western celery decreased. There were respective 29.63% and 34.33% loss on Chinese celery and Western celery after microwave heating. Blanching caused the greatest loss of apigenin contents, for example, the contents in Chinese celery reduced from 2.440mg/100g FW to 1.186mg/100g FW which had a significant difference compared with other cooking methods (P<0.05). The result also indicated that total content of 5 kinds of flavonoids detected in Chinese celery was higher than that in Western celery.(3) The changes of some sensory, nutritional and bioactive compounds in cooked (steaming, stir-frying) Chinese celery which was stored at cold and tempering condition were also studied. The results indicated that the hardness, contents of chlorophyll and ascorbic acid were all gradually decreased while the total phenol contents and antioxidant capacity increased significantly during the storage. The sensory, ascorbic acid and total phenols contents were better kept for a longer time when stored in a 4℃refrigerator.